The boom of a modern agricultural sprayer typically includes folding wing structure that unfolds to a working width of 90 to 120 feet or more. The sprayer operator can apply chemicals at speeds ranging from 10 to 20 mph, and it is not uncommon for the boom to impact an obstacle in the field during sprayer operation. The sprayer boom wing structure can experience catastrophic damage rendering the sprayer unusable if the boom impacts an immovable object such as a telephone pole. The damage results in a costly and time-consuming wing repair. To reduce or eliminate such impact damage, various boom fold structure linkages have been devised to allow outer wings or the boom wing which is attached to the boom center frame to fold rearward during an impact. The amount of rearward travel must be adequate to allow several feet of the boom structure to clear an obstacle. If a hydraulic breakaway cylinder is utilized in the system, the boom impact energy must be sufficiently absorbed hydraulically before the cylinder reaches full stroke. Some presently available hydraulic systems include a complex and expensive cylinder with built-in cushioning orifices. The hydraulic system can be very complicated and expensive. Finding an economical breakaway system which can absorb sufficient amounts of the impact forces to limit overall boom loading to non-destructive levels while at the same time preventing excess boom momentum and oscillation has been a continuing source of problems.